1. Field of the Invention
This invention relates generally to shielding electromagnetic interference/radio frequency interference (EMI/RFI) fields and, more particularly, to shielding sensitive local human body tissue parts from potential harmful electromagnetic fields emanating from close proximity direct line-of-sight wireless transmit/receive electronic equipment antenna source.
2. Description of the Related Art
There is much concern throughout the world that electromagnetic field radiation and microwave radiation may cause human body tissue damage. The antenna and the body of wireless transmit/receive electronic equipment such as a cellular telephone and higher frequency band transceivers come in close contact with a person head or sensitive human body tissue part thereby creating a close exposure to electromagnetic field and microwave radiation. Because of these hazards and to offer some protection against these hazards, some form of shielding devices were invented. Current state-of-the-art provide accessories for cellular telephones or higher frequency band transceivers that will afford some protection to cellular telephone and higher frequency band transceiver users from the alleged brain, head and sensitive body tissue damage caused by electromagnetic field radiation of cellular telephone or higher frequency band transceiver use. These accessories are primarily of closed-form design solutions around the electronic equipment to reduce electromagnetic field radiation emanating from the electronic equipment body, but does not attempt to sufficiently reduce electromagnetic field radiation from the antenna, regarding direct line-of-sight signal transmission between the antenna and the sensitive human body tissue part without causing serious impact to normal signal transmission operation.
Some attempts to implement closed-form method shielding design solutions around electromagnetic field radiation from an electronic equipment antenna would be very difficult to implement without causing tremendous antenna transmit/receive signal degradation for the equipment and still be effective in providing sufficiently adequate shielding for the user. Strict and exacting design parameters and controls over time of equipment operation on shield spacings, positioning, shield part dimensions and material electrical characteristic behavior parameters under normal stress movement conditions by the user, would be required to solve the complex and specific antenna electromagnetic field frequency response voltage standing wave ratio loading and matching criteria relative to that particular antenna electrical structure design in order for proper antenna operation.
Note that for added clarification regarding the concept of closed-form method design solutions, a simplified circuit model is shown in FIG. 10, that shows a comparison between the closed-form versus opened-form method design solutions as applied to close-proximity electromagnetic field radiation exposure to the user. Also note that the basic distinction for the closed-form method design solutions is for the shielding to encompass around the electronic equipment body or antenna as noted by the diagrammed reference node point to antenna. But with regards to the opened-form method design solution, is the shielding to encompass around the human body user part as noted by the diagrammed reference node point to user. Further note, if we were to start with the same finite small closed-form and opened-form surface shielding area and now increase each surface area evenly further, the closed-form shielding area encompasses and terminates more electromagnetic fields from the antenna thereby increasing the design sensitivities and interactions, whereas for the opened-form shielding area does not encompass or terminate electromagnetic fields appreciably to affect the antenna operation any further for matters that would be appreciated by those skilled in the art.
What is needed is an opened-form method design solution that is simply detached from the design requirement of solving for complex antenna matching criteria parameters and now centered the design solution around the exposed electronic user body part, serving means to provide an electromagnetic field radiation shielding or blockage, either reflective or absorptive or dissipative behavior in nature, in order to reduce the direct line-of-sight antenna electromagnetic field radiation to the sensitive human body tissue part without causing significant antenna signal transmit/receive degradation for proper wireless electronic equipment operation and simplifying the shielding device design, irrespective of any antenna strict electrical and structure matching criteria that would be imposed if one were to use parameters for closed-form method design solutions, thus simplifying the present invention fabrication, improving performance reliability and repeatability of the present invention.